Maximum Fe Content Research Articles

Medium optimization to improve growth and iron uptake by Bacillus tequilensis ASFS1 using fractional factorial designs

Many notable applications have been described for magnetic nanoparticles in delivery of diverse drugs and bioactive compounds into cells, magnetofection for the treatment of cancer, photodynamic therapy, photothermal therapy, and magnetic particle imaging (MPI). In response to the growing demand for magnetic nanoparticles for drug delivery or biomedical imaging applications, more effective and eco-friendly methodologies are required for large-scale biosynthesis of this nanoparticles. The major challenge in the large-scale biomedical application of magnetic nanoparticles lies in its low efficiency and optimization of nanoparticle production can address this issue. In the current study, a prediction model is suggested by the fractional factorial designs. The present study aims to optimize culture media components for improved growth and iron uptake of this strain. The result of optimization for iron uptake by the strain ASFS1 is to increase the production of magnetic nanoparticles by this strain for biomedical applications in the future. In the present study, design of experiment method was used to probe the effects of some key medium components (yeast extract, tryptone, FeSO4, Na2-EDTA, and FeCl3) on Fe content in biomass and dried biomass of strain ASFS1. A 25−1 fractional factorial design showed that Na2-EDTA, FeCl3, yeast extract-tryptone interaction, and FeSO4-Na2-EDTA interaction were the most parameters on Fe content in biomass within the experimented levels (p < 0.05), while yeast extract, FeCl3, and yeast extract-tryptone interaction were the most significant factors within the experimented levels (p < 0.05) to effect on dried biomass of strain ASFS1. The optimum culture media components for the magnetic nanoparticles production by strain ASFS1 was reported to be 7.95 g L−1 of yeast extract, 5 g L−1 of tryptone, 75 μg mL−1 of FeSO4, 192.3 μg mL−1 of Na2-EDTA and 150 μg mL−1 of FeCl3 which was theoretically able to produce Fe content in biomass (158 μg mL−1) and dried biomass (2.59 mg mL−1) based on the obtained for medium optimization. Using these culture media components an experimental maximum Fe content in biomass (139 ± 13 μg mL−1) and dried biomass (2.2 ± 0.2 mg mL−1) was obtained, confirming the efficiency of the used method.

Biochemical Characterization and Phytochemical Analysis of Different Buckwheat Germplasm in Mid Hill of Sikkim

A study was conducted during November–February of 2021–2022 and 2022–2023 at ICAR RC for NEH Region, Sikkim Centre, Gangtok, Sikkim, India for biochemical characterization, mineral and phytochemical contents of different buckwheat germplasm following standard analysis protocol. The results revealed that accession along with the variety were found to be superior for the desirable nutritional quality parameters in comparison with local variety Titey. The protein content was highest in Titey (11.2%) followed by Shimla B-1 (11.1%) and lowest in IC49671 and IC108510 (10.4%). Significant variation was estimated for tryptophan content for various genotypes ranges from 66.3 to 76.9 mg g-1 N. The crude fibre content showed the range of variation from 3.71 to 4.78% in dry mature grains of tartary buckwheat %. Maximum nitrogen free content was recorded in IC108518 (76.97%) followed by IC202268 (75.37%) and lowest was found in IC36805 (71.41%). Maximum Fe content was found in genotype IC108518 (3.50) followed by IC109549 (3.49) and lowest was recorded in genotype IC49671 (2.50 mg 100 g-1). Similarly, total phenol content ranged from 378.41 to 652.71 mg GAE 100 g-1 with an average content of 518.68 mg GAE 100 g-1. Therefore, development and utilization of such functional foods will not only improve the nutritional status of the poor people but also helps those suffering from degenerative diseases. Wide variations among genotypes for quality attributes have shown ample potential to be exploited for further improvement of desirable quality attributes and other properties. This is the first-time study for biochemical and phytochemical analysis of buckwheat in Sikkim condition.

An Invitation on Characterization of H2-Reduced Bauxite Residue and Recovering Iron through Wet Magnetic Separation Processes

Recovering iron from the bauxite residue (BR) is one of the long-standing challenges in the mining industry. However, there is a substantial lack of information in the literature regarding sample properties and iron extraction by reducing hydrogen. The present study aims at reducing a Greek BR using hydrogen, its characterization, and separating iron by magnetic separation processes. To this end, the reduced sample was characterized using X-ray diffractometry analysis (XRD), X-ray fluorescence spectrometer analysis (XRF), thermomagnetic analysis (TMA), automated mineralogy (AM), and scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS). The effect of particle size (−200 + 100 µm, −100 + 75 µm, and &lt;75 µm) was investigated through a medium-intensity magnetic separation (MIMS, Davis Tube) at 1000–2500 Gauss and a Slon® magnetic separator (1000 G). The effects of solid content (3% and 10% w/w) in a wet low-intensity magnetic separation (WLIMS, 350 G) and a two-stage MIMS followed by WLIMS were investigated. It was revealed that through reduction at 500 °C and 2 h with 20 wt% NaOH under 5 vol.% H2 + 95 vol.% N2, iron oxides and ferric oxyhydroxide (Fe2O3 and FeOOH) were converted into magnetite (Fe3O4), whereas aluminum (oxy)hydroxides (Al(OOH), Al(OH)3) were reacted with Na+ towards sodium aluminates (NaAlO2). The AM observations indicated that only 3% of iron was in the phase of liberated magnetite, and the remaining was associated with Na, Al, and Ti phases with different intensities. The dissemination of iron throughout the matrix of the sample was recognized as the principal challenge in the physical separation processes. It was found that increasing magnetic intensity from 1000 G to 2500 G resulted in improved recovery for all studied particle size fractions in Davis Tube tests. The particle range of −106 + 74 µm was chosen as the most appropriate size to achieve the maximum Fe content of 41%. The results of WLIMS (350 G) showed the maximum Fe grade but revealed less recovery of 52% and 27% at 10% and 3% solid contents, respectively, compared to the Davis Tube trials.

Recovery of Rare Earth Elements from Spent NdFeB-Magnets: Separation of Iron through Reductive Smelting of the Oxidized Material (Second Part)

This paper proposes a pyrometallurgical recycling method for end-of-life NdFeB magnets by oxidizing them in air and subsequently smelting them. The smelting process enabled the recovery of rare earth elements (REEs), producing a new reach concentrate separating the iron as a metallic phase. From the products of smelting, the metallic phase showed a maximum Fe content of 92.3 wt.%, while the slag phase showed a maximum total REE (Nd, Pr, and Dy) content of 47.47 wt.%, both at a smelting temperature of 1500 °C. ICE-OES and XRD analysis were conducted on both phases, and results showed that the metal phase consists mainly of Fe and Fe3C while the slag phase consists of the RE-oxides, leftover Fe2O3, and a mixture of Fe6Nd4. The obtained slag concentrate based on the oxides of rare earth elements is suitable for further pyrometallurgical or hydrometallurgical treatment in order to obtain rare earth elements.

Mitigation of groundwater iron-induced clogging by low-cost bioadsorbent in open loop geothermal heat pump systems

Green energy production from natural resources can reduce emissions of greenhouse gases and pollutants from burning of fossil fuels in power plants. Recently, groundwater geothermal energy (GGE) is harnessed by deploying closed- and open-loop heat systems. In open-loop geothermal heat pump systems (OLGHPS), groundwater is reinjected into aquifer after harnessing GGE. Nevertheless, OLGHPS face noxious clogging issue because of elusive chemistry (corrosion or precipitation) of chemical species, principally of iron (Fe), in pipes and aquifers during reinjection process via oxidation reactions. Plethora of filtering materials are available for removal of ions, but these are quite expensive and environmentally unsafe. More recently, low-cost, eco-friendly, green filtering materials gain much interest. These materials can remove ions from groundwater that can minimize clogging in heat exchange systems, injection wells, and aquifer. In the present study, three filtering materials, i.e., wooden charcoal (biomaterial), yamazuna fine sand, and volcanic ash, were tested to estimate their Fe removal capacity. In upward flow mode with minimum oxygen-water contact, serial column (each with 6 ports) experiments were conducted under constant pressure head and constant velocity conditions. Columns were connected to well water having dissolved Fe concentration of 10.85 mg L−1. Sampling was done at the well, column inlets, column’s six sampling ports and column outlets, and samples were analyzed for Fe by atomic absorption spectroscopy. Related tested parameters include pH, EC, temperature, turbidity, porosity, particle diameter, and dissolved oxygen. Volcanic ash showed less Fe removal, while sand filter showed substantial reduction in velocity. Biomaterial (wooden charcoal) displayed higher Fe adsorption capacity compared to other materials that can be ascribed to its surface chemistry and functional groups. Under different flow rates, maximum Fe content of 3.5 g Fe kg−1 dry charcoal was obtained. By considering a safety factor and influence of groundwater composition, it is possible to design a biomaterial-based iron filter system to minimize Fe-induced chemical clogging in OLGHPS which is an eco-friendly, green energy source.

FeNbBP type nanocrystalline alloy with high B s of 1.64 T optimized by sputtered thin film method

The increasing of saturation magnetic flux density (Bs) in FeNbB type nanocrystalline alloy has been widely studied. The influence of additional element to improve Amorphous Forming Ability (AFA) in precursor was investigated using substrate temperature controlled sputtering method at 523K. The AFA was improved by the addition of P, Si, V, or Mo, was decreased by the addition of Y, Cu, or Ge. Especially, the addition of 1 at% P exhibited a good effect of obtaining 85 at% of maximum Fe content with high stable amorphous precursor. The addition of P or C increased Bs. The Fe85Nb6B8P1 nanocrystalline alloy ribbon showed stable amorphous phase as quenched, exhibited a homogeneous nanocrystalline structure composed of grains with 10 to 20 nm in diameter after nanocrystallization. The ribbon exhibited high Bs of 1.64T and low coercivity of 10 A/m.

Screening of Some High Iron and Zinc Containing Varieties of Rice (Oryza sativaL.)

Screening of rice varieties for high iron (Fe) and zinc (Zn) content and uptake in rice grain was conducted at Crop Research Station Masodha, N.D. University of Agriculture and Technology, Kumarganj, Faizabad during kharif seasons of 2007 and 2008. Ten promising rice varieties have been chosen from previous screening experiments and with consultation of breeders for further screening for high Fe and Zn content and uptake in white rice and brown rice. Among the varieties studied, Karthika recorded maximum grain yield (6.0 t ha−1), yield atributing parameters, N, P, K content and uptake followed by variety R-979-67-2 (5.77 t ha−1) and minimum by Jhelam (1.95 t ha−1). Zinc and Fe content and uptake in grain (white rice) and brown rice varied significantly among the varieties. Variety ADT-43 registered maximum Zn content (26 mg kg−1) and variety R-979-67-2 registered maximum Zn uptake (121 mg kg−1) in white rice, whereas NDR6279 registered maximum Zn content (66.0 mg kg−1) and uptake (371.6 mg kg−1) in brown rice. Maximum Fe content was registered by variety Jhelum (63 mg kg−1) and maximum Fe uptake by variety Karthika (210 mg kg−1) in white rice, while in brown rice maximum Fe content was registered by IR-36 (83 mg kg−1) and maximum Fe uptake by Khitish (401.9 mg kg−1). On an average brown rice registered 250 per cent increase in Zn content and Zn uptake over white rice, whereas in case of Fe there was 164 per cent increase in content and uptake by brown rice over white rice. Varieties NDR-6279, Karthika and Khitish were found superior in respect of yield, yield atributing parameters, N, P, K, Zn and Fe content and uptake in white and brown rice.

Influence of Fe impurities on structure and properties of arc-evaporated AlCrN coatings

The influence of up to 5at.% Fe in AlCr targets on microstructure and properties of arc-evaporated AlCr(Fe)N coatings is investigated. Analyses of the coatings by electron microscopy and X-ray diffraction reveal no significant changes in their microstructure. The incorporated Fe atoms are homogeneously distributed and mainly substitute Cr and Al atoms in the crystal lattice as suggested by elemental mappings, X-ray photoelectron spectroscopy and X-ray diffraction. There is no pronounced modification of the mechanical properties due to the Fe addition. However, thermogravimetric analysis in oxygen containing atmosphere reveals a reduction of the oxidation onset temperature due to the addition of Fe reaching 700–800°C for the maximum Fe content studied. Raman spectra recorded from oxidised coatings indicate that the presence of Fe in the coatings promotes the formation of Cr2O3 at lower temperatures than for the reference AlCrN. This lower oxidation onset results in a reduced wear resistance at temperatures up to 700°C. Nevertheless, the presence of Fe retards the ongoing oxidation reaction at temperatures exceeding 1000°C, indicating the formation of a dense oxide scale.

Scaffolding, Ladders, Chains, and Rare Ferrimagnetism in Intermetallic Borides: Electronic Structure Calculations and Magnetic Ordering

The electronic structures of "Ti(9-n)Fe(2+n)Ru(18)B(8)" (n=0, 0.5, 1, 2, 3), in connection to the recently synthesized Ti(9-n)Fe(2+n)Ru(18)B(8) (n=1, 2), have been investigated and analyzed using LSDA tight-binding calculations to elucidate the distribution of Fe and Ti, to determine the maximum Fe content, and to explore possible magnetic structures to interpret experimental magnetization results. Through a combination of calculations on specific models and using the rigid band approximation, which is validated by the DOS curves for "Ti(9-n)Fe(2+n)Ru(18)B(8)" (n=0, 0.5, 1, 2, 3), mixing of Fe and Ti is anticipated at both the 2b- and 4h-chain sites. The model "Ti(8.5)Fe(2.5)Ru(18)B(8)" (n=0.5) revealed that both Brewer-type Ti-Ru interactions as well as ligand field splitting of the Fe 3d orbitals regulated the observed valence electron counts between 220 and 228 electrons/formula unit. Finally, models of magnetic structures were created using "Ti(6)Fe(5)Ru(18)B(8)" (n=3). A rigid band analysis of the LSDA DOS curves concluded preferred ferromagnetic ordering at low Fe content (n≤0.75) and ferrimagnetic ordering at higher Fe content (n>0.75). Ferrimagnetism arises from antiferromagnetic exchange coupling in the scaffold of Fe1-ladder and 4h-chain sites.

Preparation of continuous Si-Fe-C-O functional ceramic fibers

A new polymer named polyferrocarbosilane(PFCS) was prepared from polydimethylsilane and ferrocene. The spinnability of this polymer can be tailored by controlling the content of ferrocene in the polymer. The prepared polymer was spun into a continuous polymer fiber that was subsequently cured in air and heat-treated finally in N 2 up to 1350 °C for conversion into Si-Fe-C-O fibers. The resulted Si-Fe-C-O fibers display low specific resistance and magnetic property due to the existence of Fe, which also reduces the specific resistance significantly to 10 −2 Ωcm at room temperature when the amount of ferrocene in feed is as low as 3.0% (mass fraction). The resulted Si-Fe-C-O fibers, with C/Si molar ratio of about 1.3 and the maximum Fe content of about 2.0% (mole fraction), are composed of β-SiC and small amount of Fe 3Si-like crystalline and have an average tensile strength of about 2.0 GPa.

Effect of Fe addition on transformation temperatures and hardness of NiMnGa magnetic shape memory alloys

In recent years, ferromagnetic shape memory alloys (FSMAs) have been widely investigated in many countries [1–4]. Of the developed FSMAs, NiMnGa alloys have been found to exhibit nearly 10% magnetic-fieldinduced strain which is the maximum obtained MFIS in these FSMAs [5]. Based on NiMnGa alloys, researchers have developed new ferromagnetic shape memory alloys, i.e., NiMnFeGa alloys [6, 7]. The structure, shape memory effect, and magnetic properties of Fe-doped NiMnGa alloys have been studied. It is assumed that the addition of Fe element enhances the alloy plasticity without sacrificing its magnetic and thermoelastic properties [6]. However, little work has been devoted to studying transformation behavior and the mechanical properties of polycrystalline Fe-doped NiMnGa alloys. The aim of the present letter is to study the effect of additions of Fe on transformation behavior and the hardness of NiMnGa alloys. A range of alloys with the nominal composition of Ni48.7Mn30.1−x Fex Ga21.2 (at%) (x = 0, 2, 5, 8, 11), each weighing about 80 g, were prepared. The alloys were fabricated by arc melting under an argon atmosphere using appropriate quantities of nickel (99.99% purity), manganese (99.9% purity), iron (99.9% purity) and gallium (99.99% purity). The ingots obtained were sealed in a quartz tube under a vacuum, followed by annealing at 1123 K for 24 hrs and quenched into ice water for homogeneity. Rectangular samples 4×4×6 mm were cut from the post-treated ingots for hardness measurements. Some 10 mg samples were taken from the ingots for DSC measurements. The transformation temperatures were determined by differential scanning calorimetry using a TA-2920. The heating and cooling rates were 10 K/min. The crystal structure at room temperature was confirmed by powder X-ray diffraction using D/MAX-RA X-ray diffractometer with Cu Kα radiation. Micro Vickers hardness (HV) of eight points was measured using a Akashi HM-102 Vickers Hardness Tester. The applied load and time were 200 g and 15 s, respectively. The HV values were averaged excluding the highest and lowest values [8]. Table I summarizes the transformation temperatures measured by DSC analysis in Ni48.7Mn30.1−x Fex Ga21.2 alloys (x = 0, 2, 5, 8, 11). It can be seen, at room temperature, that the parent phase and martensite coexist in the Ni48.7Mn30.1Ga21.2 alloy and the Ni48.7Mn28.1Fe2Ga21.2 alloys, whereas in the other three alloys only the parent phase exists. The results are in agreement with X-ray diffraction results in Fig. 1. X-ray patterns depict that the cubic parent phase and tetragonal martensite coexist when x = 0, 2, while only the cubic parent phase exists when x = 5, 8, 11. As shown in Table I, the thermal hysteresis of these five alloys are −1.38, −3.30, 0.46, 2.60 and 2.20 ◦C, respectively. For the Ni48.7Mn30.1Ga21.2 alloy and the Ni48.7Mn28.1Fe2Ga21.2 alloys, the thermal hysteresis is negative. Hence Fe-doped NiMnGa alloys exhibit very narrow thermal hysteresis which means that the chemical energy of the phase transformation is very small. The narrow thermal hysteresis also shows that the driving force for inducing the martensitic transformation in Fe-doped NiMnGa alloy is very small. Wayman [9] divided thermal transformations into two types: the first is Af > As > Ms > Mf while the second is Af > Ms > As > Mf. From Table I it can be seen that the first two alloys belong to the second type of thermal transformation, while the other three alloys belong to the first type of thermal transformation. In addition, only single forward and reverse transformation are determined by DSC curves. Fig. 2 depicts the phase transformation temperatures vs. Fe content for Ni48.7Mn30.1−x Fex Ga21.2 alloys (x = 0, 2, 5, 8, 11). It can be seen that with increase of Fe content all the transformation temperatures, Ms (martensitic transformation start temperature), Mf (martensitic transformation finish temperature), As (reverse martensitic transformation start temperature), and A f (reverse martensitic transformation finish temperature), decrease. The relationship between Ms temperature and Fe content is nearly linear, varing from 26.40 ◦C for Ni48.7Mn30.1Ga21.2 without Fe to −55.00 ◦C for Ni48.7Mn19.1Fe11Ga21.2 which has the maximum Fe content. Fig. 3 exhibits the relationship between transformation temperatures and valence electron numbers per atom of Ni48.7Mn30.1−x Fex Ga21.2 alloys (x = 0, 2, 5, 8, 11) and the shape of the curves is similar to Fig. 2. The tendency is clear that all transformation temperatures decrease with increase of electronic concentration in these five alloys, and the increasing rate is also basically consistent with the change of the electronic concentration. Here, it is assumed that the number of valence electrons per atom for Ni, Mn, Fe, and Ga atoms is 10(3d84s2),7(3d54s2),8(3d64s2) and 3(3s24p1), respectively. It is believed that two factors, the conduction electronic concentrations [10] and the size factor [11],

Identification and regional quantification of hydrochemical processes at the contact zone between anoxic groundwater and surface water in poldered floodplains (Oderbruch polder, Germany)

The hydrochemistry in the largest polder of the Oder River, named Oderbruch, is affected by long-term infiltration of water from the Oder into the aquifer below an alluvial loamy top layer of the polder. These exceptional hydraulic conditions are a result of dyke constructions which were built more than 250 a ago. The objective of this investigation is a better understanding and a characterisation of the contact zone between the anaerobic groundwater and the surface water of a vast drainage system. Induced by changing water levels, different hydraulic conditions occur, which strongly influence the hydrochemistry of the shallow aquifer and therefore the natural sink function of the polder area. Field investigations with a hydrochemical and hydraulic characterisation of selected drainage ditch locations show considerable chemical interactions between groundwater and surface water. Depending on the drainage ditch type, which is defined by the hydraulic situation, the redox processes create a chemical gradient combined with a distinct enrichment of Fe and Mn. The source of the high amounts of Fe and Mn in the groundwater are reduced Fe- and Mn-hydroxides from the aquifer sediments. Under exfiltrating conditions interrupted by dry phases, more than 50 g kg −1 Fe and 0.25 g kg −1 Mn have accumulated in the drainage ditch floor sediments since the construction of the drainage ditches 35 a ago. The results show a very effective fixation of trace metals in the drainage ditch sediments under these conditions. Under permanent exfiltration conditions, the enrichment of Fe and Mn is relatively low. The maximum Fe content was 4 g kg −1 sediment and the Mn content reached only 0.4 g kg −1. This is less than 10% of the mobile Fe 2+ and less than 1% of the Mn 2+ which migrates from the aquifer into the surface water.

Synthesis, Cation Distribution, and Electrochemical Properties of Fe-Substituted Li2MnO3 as a Novel 4 V Positive Electrode Material

solid solution was synthesized using solid-state reaction and hydrothermal-postannealing methods and characterized as a positive electrode material for rechargeable lithium batteries. Although the maximum Fe content was limited up to 30% by solid-state reaction, the content can extend up to 75% by the hydrothermal-postannealing method. Neutron and X-ray Rietveld analysis reveal that the basic structure of the sample is a layered rock-salt structure isostructural with in which Fe ions exist on both Li (3a) and Co (3b) sites. Elemental analysis and Mössbauer spectra show Fe ions exist as 3+/4+ mixed-valence state after the samples were postannealed above 650°C. The initial charge capacity of Li/sample cells was above 100 mAh/g when the upper voltage limit was 4.3 V. The plateau around 4 V was observed for all Li/sample cells on first discharge. The maximum of initial discharge capacity was about 100 mAh/g down to 2.5 V for the Li/(50% Fe-substituted sample) cell, when the positive electrode was obtained by postannealing at 650°C in air. The capacity fading of the 4 V plateau could be suppressed by adjusting the Fe content to less than 50%, postannealing temperature between 600 and 700°C, and by 10% Ni substitution. © 2002 The Electrochemical Society. All rights reserved.

液体急冷非晶質薄帯上に析出した無電解ＣｏＦｅ系合金めっき膜の析出挙動と性状

Co-based films were deposited electrolessly on rapid-quenched Ni-based amorphous alloy ribbons. Electroless deposition is possible autocatalytically on amorphous substrates when dimethylamine borane (DMAB) is used as the regand agent. A Co-based alloy film with a maximum Fe content of 60at% was obtained by controlling chemical composition in the bath and deposition conditions. Magnetic properties of obtained films depended on surface conditions and the ribbon substrate composition. Changes in film layer structural and magnetic properties with different film thicknesses were observed when bimetals were heat-treated at a range of temperatures that did not crystallize the ribbon.

Characterization of Fe-supersaturated Fe-Al bronze coatings fabricated by magnetron sputter deposition

Magnetron sputter deposition was used to fabricate thin films of several Fe-Al bronze alloy compositions. Electron microscopy and X-ray diffraction were employed to evaluate the structure and composition of the films, and to determine the extent of Fe supersaturation. It was found that magnetron sputtering is an effective method for creating Fe-Al bronze alloys supersaturated with Fe. The maximum Fe content obtained in a sputtered film was 9.8%, well above the normal equilibrium solubility limit of 3.5 %.

ChemInform Abstract: Preparation and Properties of Iron(II) Hydroxide‐(Sodium Fluoride Tetrasilicic Mica) Intercalation Complexes.

AbstractIron(II) hydroxide‐mica complexes of ideal composition (Fe3(OH)5(H2O)) (Mg2.5Si4O10F2) at maximum Fe content are prepared by titration of mica containing FeSO4 solutions with NaOH under oxygen‐free conditions.

Fe solubilities in very saline hydrothermal fluids; their relation to zoning in some ore deposits

The Fe concentrations in fluids present in very saline fluid inclusions from the King Island W skarn, hole 16, F-Sn-W deposit and the Mary Kathleen U-rare earth element skarn have been determined using the phase deposit volume method. Fe-bearing daughter minerals include magnetite, pyrite, amarantite (Fe (super +3) (SO 4 )(OH) . - 3H 2 O), and hydrated ferrous chloride. The fluid inclusion liquid compositions are inferred from a combined analysis of first melting temperatures (= eutectic temperatures of the salt system), daughter crystal identification by scanning electron microscopy in conjunction with an energy dispersive X-ray analyzer, and relevant published experimental salt solubilities. Maximum Fe solubilities show an exponential increase to 9 wt percent Fe with increasing total anion content of the fluid, especially in the 20 to 30 wt percent interval. Fe solubility is mainly dependent on total chloride contents, with fluoride contributing very little to increasing the Fe solubility. Temperature, f (sub O 2 ) , and f (sub S 2 ) appear to have a minor influence on the total Fe solubilities.Some of the samples contain solid Fe-bearing crystals which coexisted with the fluid inclusions and probably buffered Fe at the appropriate a Fe values during genesis, but the Fe contents of most fluids were probably undersaturated with respect to Fe-bearing minerals. Over the range for which the total anion content of the fluid is 25 to 35 wt percent, the apparent maximum Fe content of fluids tends to decrease in the following order when the Fe-bearing daughter crystals are present: magnetite > pyrite > hydrated ferrous chloride [raquo] amarantite, although anomalies to this trend occur.The Fe solubility data are used to explain some Fe mineral overprints (stages II and III) of skarns, the magnetite-Fe chlorite-cassiterite veins in tin granites, and the zonal pattern present in porphyry copper systems. The Fe data suggest that the highly saline, Fe-bearing solutions present in the cores of porphyry systems and other near-contact deposits are not a result of increased salinity of hydrothermal fluids due to boiling of meteoric solutions but are inherent from an orthomagmatic source.